DE2459640A1 - MAGNETIC MEMORY - Google Patents

Description

Our sign; T 1643

TEXAS INSTRUMENTS INCORPORATED
13500 North Central Expressway
Dallas, Texas, V.St.A.

Magnetic storage

The invention relates to a magnetic bubble memory and, more particularly, to an arrangement of the magnetic ones Domains in such a memory to optimize the operating behavior with regard to the existing ones Domain Formation, Propagation, Detection, and Transmission Restrictions.

In recent times there has been a great deal of interest in magnetic devices that come under the generic term components are known with "bubble" domains. Such magnetic devices are, for example, in the article "Application of Ortho. Ferrites to Domain Wall Devices "in IEEE Transactions on Magnetics, Volume MAG.-5, No. 3 (1969), pages 544 to 553; they have a generally planar structure and they are made of materials that have a have easy direction of magnetization, which is substantially perpendicular to their plane. the magnetic properties, for example the magnetization anisotropy, the coercive force and the movement

Schw / Ba

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possibility are such that the device is magnetized with a magnetization in an outside the plane lying direction can be kept and that small localized single domain areas with a polarization opposite to the general direction of polarization can be maintained. Such localized areas, which can be generally cylindrical in shape, can be digital information represent. The interest in such devices is largely in their high density and in the Ability of the cylindrical magnetic domain established, regardless of the magnetic material in the plane to be in which it is formed, thereby increasing the ability to shift in the plane of the magnetic Material for performing various memory and logic functions results.

Acting on the bubbles can be done by programming currents through a pattern of conductors on the magnetic Material or by changing the surrounding magnetic field. As an example, use magnetic Domains or bubbles in thin platelets with uniaxial anisotropy with the easy axis of magnetization perpendicular to the plane of the platelet are formed from materials such as rare earth ortho rites, rare earths, aluminum and gallium substituted iron garnets or amorphous gadolinium cobalt. Because the magnetic bubbles can be transported further, deleted and treated to form logical "operations, and there their presence and their absence can be determined, these bubbles can perform many digital functions which are important in computer operation. Magnetic bubble memory arrangements offer considerable benefits Advantages, since logic, storage, counting and switching processes within a single layer of solid magnetic material can be carried out. This is in contrast to

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conventional memory arrangements in which information is transferred from one device to another via connecting conductors and high gain amplifiers have to be transported. Moreover, the real thing will be Magnetic material, for example magnetic tapes, disks or drums, mechanically on scanning and writing devices transported past to perform data operations. In the case of a magnetic bubble memory, you can these functions are performed within a continuous ferromagnetic medium, so that there is no need to use expensive interfaces. The magnetic bubbles representing the data move in the plane of thin plates of magnetic material like magnetic garnet crystals, and they can be done at high speed and with low energy be moved to precisely determined positions. The magnetic material itself remains stationary. With the advent of mixed iron garnets, substituted by rare earths, aluminum or gallium, the bit densities on the order of 1.55 * 10 bits / cm (10 bits / square "inch) is the development a reliable solid-state storage equivalent to magnetic disk or magnetic drum storage has become a particularly attractive and realistic concept.

Many forms of organization of operational domains have been proposed. The most famous storage organization is that with major and minor loops described in US Pat. No. 3,618,054. This storage organization with main and secondary loops as well as their concrete realization and their mode of operation are known in the art. The memory organization described in the patent mentioned and also in other places with main and secondary loops contains a closed main loop. This closed loop is typically based on an arrangement of permalloy

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circuits formed with T-bars on a plate made of orthorrite or garnet crystal. The bubbles circulate lengthways the loop by the action of a magnetic field rotating in the plane. The main loop is generally elongated, so that several secondary loops can be strung together on their long sides. Bi-directional transfer gates allow bubbles to be transferred from the secondary loop to the main loop and from the main loop to a secondary loop. -Another way to access the main loop is through a sense and read port and a separate write port.

The organization makes it possible that a synchronized pattern of domains in corresponding secondary loops on separate Platelets represent a binary word. The movement of the domains in the loops takes place synchronously, so that a parallel transmission Simply put the selected word in the main loops of the platelets can take place in that the number of rotations of the magnetic field lying in the plane is tracked to determine the correct transmission time.

However, numerous disadvantages can be observed. So, once the information has been removed from the secondary loops in a main loop has been transmitted, wait the full round trip cycle of the main loop before a retransmission is possible in the secondary loop. In addition, the transmission gate must be a bidirectional gate, which in itself is already more complicated than a one-way gate. Carrying out into and out of the main loop at the same point requires a reversal of the transmission sequence, so that there is a more complicated operation than the case in which all the transferring steps and feeding steps in

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one direction. Also runs in
Incorrectly generated for any reason and in
the main loop got around the bubble indefinitely,
since the main loop is a closed loop. the
Control operations to keep track of the location of data in
the orbital loops are quite complicated - given the place
of a bubble in the main loop must be tracked for its exit point from the sub-loop and kept in sync with the position of the data in the sub-loops. Furthermore, the organization with main and secondary loops does not allow continuous data transmission, since the data is transmitted from the same transmission gates into the secondary loop and from the secondary loop.

With the help of the invention, a magnetic domain organization with main and secondary loops is to be created which enables continuous data transmission. Furthermore, a magnetic domain organization with main and secondary loops for memory circuits is to be designed in such a way that the entry and exit points of the secondary loops are at different locations, thereby making operations in comparison
be simplified or accelerated to previously known structures. The use of one-way transfer gates simplifies transfer operations, while two-way gates reduce memory access time. The with the help of the invention too
creating magnetic domain organization with main and secondary
^ loops should allow the use of a simplified control unit due to the cyclical nature of all control signals. In addition, in the case of the magnetic domain organization with main and secondary loops to be created with the aid of the invention, the possible unlimited persistence of a disturbance bubble is to be eliminated
will.

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A preferred embodiment of the invention, a magnetic bubble organization with major and minor loops, which is constructed on an epitaxial, magnetic garnet plate, wherein the main loop in 'is closed ist.Zweckmässigerweise is not here in accordance with the common terminology, the term "loop" for the identification of Main domain path used, even if it is not self-contained * The path of the main loop runs past the secondary loops twice in the same order. This makes it possible to transfer bubbles back into the secondary loops at a first point via one-way transfer gates and then again via one-way transfer gates at a second point back into the secondary loops. Two-way transmission gates can also be used in both locations, and read and write ports can be placed close to each transmission location for faster access of the data to and from the slave loops. Disturbance bubbles do not circulate indefinitely, but are destroyed at the end of the main loop path. Control operations are simplified because the position of the data in a secondary loop adequately determines the position of the bubbles in the entire system at any point in time; the simplification of the control operations also results from the fact that the control signals are cyclical.

It is also possible to provide a double organization in which the main loop path runs past two rows of secondary loops one after the other, so that the path has the first row of secondary loops at a first location, the second row of secondary loops at a first location, and the first row of secondary loops at a second location and then the second row of secondary loops at a second location.

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The invention will now be explained by way of example with reference to the drawing. .

Show it

Fig.1 - a top view of a known bladder storage organization with main and secondary loops,

2 shows a plan view of a bladder accumulator organization according to the invention with main and secondary loops,

3 to 5 plan views of further inventive Embodiments of bladder storage organizations with main and secondary loops and

6 shows a plan view of an embodiment of a bladder storage organization with main and secondary loops according to the invention, with two parallel rows of Secondary loops are shown.

In Figure 1 of the drawings is a known bladder accumulator organization shown with main and secondary loops. This organization is similar to the one in, among others, the U.S. Patents 3,613,056, 3,618,054, and 3,729,726. The conditions for creating single-wall magnetic domains on a suitable material 8, for example an epitaxial magnetic garnet layer on a non-magnetic garnet substrates, are in the art known. An article on this subject is the above-mentioned article in the IEEE Transactions on Magnetics, Volume MAG-5, No. 3 (1969), pages 544 to 553. To define the loop patterns are usually patterns of magnetically soft covering material (e.g. Permalloy) with rod and T-shaped segments are used. A long loop called the main loop 10 is closed in itself, so that circulating bubbles that

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are generated in the loop, circulate indefinitely, provided that they are not transmitted to the outside.

Opposite the main loop 10, several similar secondary loops 12, 14 and 16 are lined up. A section each sub-loop (the section closest to main loop 10) acts as part of a two-way transmission gate 18 to the main loop. The transfer can be made in the manner described in the United States patent 3,618,054. Although only three secondary loops here are shown in detail, the dashed lines between the secondary loops indicate that further secondary loops can be formed. A transmit pulse transmits from each simultaneously Secondary loop a bubble (or lack of a bubble) to the main loop.

When the bubbles are in the main loop, those in the transfer direction 20 are located in the The plane rotating magnetic field is transported further, with each rotation four steps of the T-bar progression sequence as described in referenced U.S. Patent 3,618,054. The result of the succession of the bubbles the expressed data sequence passing through point 24 of the main loop is copied and read by the detector at point 22, If the write operation is indicated, the data bubbles are erased at point 24, and a generator at Point 26 can write new data into the loop at point 28, the circumferential behind point 24 lies.

In ELg.2 a domain locomotion arrangement is shown after the Invention shown. This arrangement contains a layer 8 of magnetic material in which single-wall domains are erected.

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obtained and caused to move, as above in connection with the known Organization has been discussed. One from a source 30 The bias field generated keeps single-wall domains in the material at a nominal operating size in a known manner. A rotating field source 32 causes a domain to move normally counterclockwise. To activate and synchronization, the rotating field source is under the control of a control circuit 34. The control; circuit 34 also controls the transmission gates as well the copy / delete, lock and create functions.

The bias sources, the control circuit and others Auxiliary circuits (such as pulse circuits for applying Pulses to the transmission gates, counter circuits for tracking the bubbles in the loops, etc.) are known. Such circuits are not specified in detail, but they can, if desired, according to the designs Fig. 2 and according to Fig. 3 to 6 can be used.

The organization shown in Figure 2 contains several Secondary loops, which can be regarded as similar to the secondary loops shown in Fig. 1, and a generally G-shaped main loop 40. This organization is therefore referred to as "G-track". the The main loop is adjacent to the secondary loops on two sides. The path of the main loop 40 runs on the upper side at the top of each secondary loop over, so that the transmission gates 46, 44 and 42 the connection between the secondary loops 16, 14 or 12 with the main loop 40 produce.

Assuming that the bladder locomotion, in the Main loop 40 at the top of the illustration from the right

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takes place to the left, the bubble movement in the main loop first meets the copy / Eösch point, then to plague and read port 48 and finally to write terminal 50 in a manner similar to in the arrangement of Fig.1.

At the bottom, the path of the main loop reverses so that it is again adjacent to the secondary loops 16, and 12 runs. A bubble moving in the main loop 40 passes the secondary loops in the process same order as in the upper section of the main loop. In this case, transmission gates 56, 54 and 52 provide the connection between the secondary loops and the Main loop at the lowest section of the secondary loops. Preferably the transfer points are each Secondary loop symmetrical and diametrically opposite each other, so that the distance in the secondary loop from the topmost point has the same length to the lowest point plus or minus one bubble position in each direction. The secondary loops usually contain an odd number of bubble positions. Thus the difference in distance is between two gates is a position, i.e. the distance from the transfer gate 42 to the transfer gate 52 X, and the distance from transfer gate 52 to transfer gate 42 is X-1 or vice versa.

In operation, the rotating magnetic field causes movement in the secondary loops in a counterclockwise direction. On command of a transmission circuit, not shown, a transmission pulse is sent to the transmission gates created. At this point, bubbles will be in the transfer gates 42, 44 and 46 of the respective Transfer the secondary loop to the main loop to make it stand out

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then move around in the main loop. If the Bubbles have migrated along the main loop until they hit the lower series of transfer gates 52, 54 and 56 have arrived, another pulse is applied to these transmission gates. Such a transmission pulse causes a Transfer back into the secondary loops at their lowest sections. The bubble positions in the secondary loops have been rotated so that the data is transferred back to its previous positions.

It can be seen that the data from the secondary loops into the main loop and from the main loop back into the secondary loops using one-way transfer gates can be transferred. Furthermore, the impulses causing the transmission operate the transmission gates in the same way each time, and it is none Bladder locomotion required in the opposite direction.

As explained above, there is an important one The feature of the invention is that it enables one-way transmission gates to be used. The arrangement can however, it can also be used to advantage with two-way transmission ports when it is desired to get data faster than is possible with the known arrangement of Figure 1, to be taken and entered. In this case, a two copy / erase point 53, a second * locking and read connection 49 and an additional write connection 51 can be attached, as shown in FIG Connections are attached to the transmission gate 56 in the same relationship as the connections and 50 with respect to the transmission gate 42. If thus the direction of the in-plane rotating magnetic field is opposite is reversed from normal operation, data can be sent to the

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Transmission gates (which in this case are two-way transmission gates) are removed from the secondary loops, so that they can be read at terminal 49 and that new data can be entered at write terminal 51.

In Fig.3, 4 and 5 are further embodiments of the Invention shown. In any case, there is an organization with major and minor loops, that shown in Figure 2 Organization is similar. While the main loop of Fig. 2 is in a G-track arrangement, which is shown in the At the top right corner, the path of the main loop 40a in the embodiment of FIG. 3 is reversed "G" that starts in the upper left corner. The circulation of the bubbles in the loops is clockwise in this arrangement when applying a corresponding rotating magnetic field lying in the plane.

In Fig. 4 and 5 main loops 40b and 40c are shown. In any case, the path of the loop can be viewed as starting at the bottom and describing it a sheet that forms a loop at the top. The main loop 4Ob starts in the lower left corner and the main loop 40c begins in the top right corner. The rotating magnetic field lying in the plane preferably rotates counterclockwise in FIG. 4, thus causing bubbles move counterclockwise in the main loop; In the execution ofFig. 5 the rotating magnetic field would turn clockwise to move bubbles in the main loop clockwise.

A double organization is shown in FIG. At this Organization, two preferably parallel rows of secondary loops are formed in the magnetic material 8. The top row the minor loop contains loops 60, 62 and 64 (along with other intervening loops like it

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for the formation of the desired storage structure is appropriate " ). In the same way, the secondary loops 66, 68 and 70 form, from right to left, three of the secondary loops of the lower group,

In this case, the main loop 71 forms what may be referred to as a "double-G" arrangement. The main loop 71 can be viewed as starting in the upper right corner of the illustration. From there it runs successively from right to left past the secondary loop 60, the secondary loop 62 and the secondary loop 64 past their upper sections and then from left to right past the secondary loop 70, the secondary loop 68 and the secondary loop 66 past their lowest sections , whereupon it passes from right to left on the "secondary loop 60, the secondary loop 62 and the secondary loop 64 at their lowest sections and finally from left to right on the secondary loop 70, the secondary loop 68 and the secondary loop 66 past their lower section.

It should be noted in this embodiment that the main loop still has the secondary loops in both sections of the course happens in the same order, the order being opposite in the two loop groups is. When all the secondary loops are in

of the organization are in the same sequence of storage elements, then this order is allowed, since the main loop passes through all secondary loops in both groups once before it meets the secondary loops in the first group for the second time.

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As before in the embodiments of FIGS One-way transfer gates are used in each of the top and bottom sections of the sub-loops for bubble transfer will. The arrows indicated at the transmission gates 72 to 83 are in the direction of the one-way transmission in normal operation drawn.

It can be seen that the read port 85 and the write port 87 "with respect to the main loop are attached where the main loop passes all secondary loops once before it also passes the first secondary loop for the second time. Here, too, is the same function as in the embodiment of Fig.2.

The "double-G organization" of Figure 6 can be broken down into one of four Patterns are rearranged which are similar to the patterns of Fig.3 to with respect to Fig.2.

Although the invention has been described here in connection with specific exemplary embodiments, the Those skilled in the art will readily recognize that within the scope of Invention further modification options are given.

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Claims (15)

"^1Γ>" 2459ΒΑ0 Claims Magnetic memory comprising a non-magnetic substrate, one mounted on a surface of the substrate, for Maintaining magnetic domains suitable body of magnetic material, one associated with the body • Arrangement for the generation and controllable positioning of magnetic domains in the magnetic material, with the magnetic domains in a main loop and in several secondary loops are organized, which are arranged for the transmission of domains, characterized in that that the main loop (40; 40a; 40b; 40; 71) is not closed and a path adjoining the secondary loops along two sides of these secondary loops is such describes that a domain moving in the main loop without transmission traverses the sub-loops happened twice in the same order, 2. Memory according to claim. 1, characterized in that the magnetic domains are organized in the non-closed main loop that a first number and a second Number of secondary loops (60 to 64, 66 to 70) for the transfer of domains are arranged and that the track of the main loop adjacent to the first number and the second number of secondary loops along two sides of the Secondary loops run in such a way that a domain moving in the main loop without transmission is the first Number of secondary loops (60 to 64) along their first side in a first order, the second number of Minor loops (66 to 70) along their second side in a second order, the first number of minor loops along its second side in the first order and the second number of secondary loops along its second side happened in the second order. 509828/0794 3 · Memory according to claim 2, characterized in that the first number and the second number of secondary loops (60 to 64, 66 to 70) are geometrically aligned in parallel rows. 4. Memory according to one of claims 1 to 3 »characterized in that the path of the main loop with respect to each of the secondary loops runs in a corresponding manner. 5. Memory according to one of claims 1 to 4, characterized in that the path of the main loop to Domain transfer each of the secondary loops happens at symmetrical points. ■ 6. Memory according to one of the preceding claims, characterized characterized in that one-way transmission gates (42 to 56; 72 to 83) are attached. 7. Memory according to one of claims 1 to 5, characterized in - that between the main loop and two-way transmission gates (42 to 56; 72 to 83) are attached to the secondary loops. 8. Memory according to one of the preceding claims, characterized in that the magnetic material is an orthoferrite plate is. 9. Memory according to one of claims 1 to 7, characterized in that the magnetic material is a single crystal plate made of magnetic garnet. 10. Memory according to one of claims 1 to 7, characterized in that that the magnetic material consists of a film of magnetic garnet (8) which is attached to a non-magnetic garnet substrate. 509828/0794 11. Memory according to one of claims 1 to 7, characterized
characterized in that the magnetic material is a
amorphous gandolinium cobalt thin film (8). 12. Memory according to one of the preceding claims,
characterized in that the arrangement for generating and controllable positioning of magnetic domains contains permalloy circuits with T-bars. 13. Memory according to one of claims 1 to 11, characterized in that the arrangement for generating and Contains controllable positioning of magnetic domains Permalloy circuits with Y-rods. 14. Memory according to one of claims 1 to 11, characterized in that the arrangement for generating and controllable positioning of magnetic domains
Contains permalloy circuits with angled parts. 15. Memory according to one of claims 1 to 11, characterized in that the arrangement for generating and controllable positioning of magnetic domains
Contains permalloy circuits with X-bars. 509828/0794